1. Field of Invention
The invention relates to a bicycle hub and, in particular, to a bicycle hub that is easy to assembled and maintained and has a very good transmission effect.
2. Related Art
A conventional hub transmission structure, as shown in FIG. 10, mainly consists of a housing 91 and a chain wheel base 93 connected inside the housing 91. The housing 91 has an inner hole 94 whose inner ring surface is formed with a ratchet ring 95. One end part of the chain wheel base 93 is accommodated in the inner hole 94 of the housing 91. The end part has a claw base 96. The claw base 96 is elastically pressed by a ring spring 97, pushing a plurality of claws 98 against the claw base 96. One end of each of the claws 98 is elastically pressed by the ring spring 97 so that its other end rises and matches with the ratchet ring 95 of the housing 97. The chain wheel base 93 is thus only allowed to drive the housing 91 in a single direction.
However, the above-mentioned hub transmission structure relies on the ring spring 97 to fix the claws 98 on the claw base 96. Therefore, once the ring spring 97 has elasticity fatigue or some deformation, as shown in FIG. 11, the forces imposed on the claws 98 become uneven. The claws 98 and the ratchet ring 95 cannot engage firmly, and the transmission efficiency is greatly reduced. The problem can be as serious as sliding. Moreover, to replace the ring spring 97 or if one of the claws 98 breaks, all the claws 98 will be released immediately after the user removes the ring spring 97. This is because they are originally positioned by the ring spring 97. So the user needs to re-assemble all the claws 98 in each replacement. This is very inconvenient for maintenance.